Disposable syringes are in widespread use for a number of different types of applications. For example, syringes are used not only to withdraw a fluid (e.g., blood) from a patient but also to administer a medication to a patient. In the latter, a cap or the like is removed from the syringe and a unit dose of the medication is carefully measured and then injected or otherwise disposed within the syringe.
As technology advances, more and more sophisticated, automated systems are being developed for preparing and delivering medications by integrating a number of different stations, with one or more specific tasks being performed at each station. For example, one type of exemplary automated system operates as a syringe filling apparatus that receives user inputted information, such as the type of medication, the volume of the medication and any mixing instructions, etc. The system then uses this inputted information to disperse the correct medication into the syringe up to the inputted volume.
In some instances, the medication that is to be delivered to the patient includes more than one pharmaceutical substance. For example, the medication can be a mixture of several components, such as several pharmaceutical substances.
By automating the medication preparation process, increased production and efficiency are achieved as well as achieving an increase in patient safety since manual manipulation, a principal cause of microbial contamination, is avoided. This results in reduced production costs and also permits the system to operate over any time period of a given day with only limited operator intervention for manual inspection to ensure proper operation is being achieved. Such a system finds particular utility in settings, such as large hospitals, including a large number of doses of medications that must be prepared daily. Traditionally, these doses have been prepared manually in what is an exacting but tedious responsibility for a highly skilled staff. In order to be valuable, automated systems must maintain the exacting standards set by medical regulatory organizations, while at the same time simplifying the overall process and reducing the time necessary for preparing the medications.
Because syringes are used often as the carrier means for transporting and delivering the medication to the patient, it is advantageous for these automated systems to be tailored to accept syringes. However, the previous methods of dispersing the medication from the vial and into the syringe were very time consuming and labor intensive. More specifically, medications and the like are typically stored in a vial that is sealed with a safety cap or the like that protects a penetrable membrane. The material can then be added to or removed from the vial by penetrating the membrane with a needle. In conventional medication preparation, a trained person retrieves the correct vial from a storage cabinet or the like, confirms the contents and then removes the safety cap manually. This is typically done by simply popping the safety cap off with one's hands. Once the safety cap is removed, the trained person inspects the integrity of the membrane and cleans the membrane. An instrument, e.g., a needle, is then used to pierce the membrane and withdraw the medication contained in the vial. The withdrawn medication is then placed into a syringe to permit subsequent administration of the medication from the syringe.
FIG. 3 illustrates an exemplary conventional syringe 10 that includes a barrel 20 having an elongated body that defines a chamber that receives and holds a medication that is disposed at a later time. The barrel 20 has an open proximal end with a flange being formed thereat and it also includes an opposing distal end that has a barrel tip 22 that has a passageway formed therethrough. An outer surface of the barrel tip or luer 22 can include features to permit fastening with a cap or other type of enclosing member. For example, the luer can have threads that permit a tip cap to be securely and removably coupled to the barrel tip 22 or to permit some other type of fitting or connector to be attached thereto. As previously mentioned, the term “medication” refers to a medicinal preparation for administration to a patient and most often, the medication is contained within the chamber 30 in a liquid state even though the medication initially may have been in a solid state, which was processed into a liquid state.
The syringe 10 further includes a plunger 24 that is removably and adjustably disposed within the barrel 20. The plunger 24 can draw a fluid (e.g., air or a liquid) into the chamber by withdrawing the plunger 24 from an initial position where the stopper is near or at the barrel tip or luer 22 to a position where the stopper is near the proximal end of the barrel 20. Conversely, the plunger 24 can be used to expel or dispense medication by first withdrawing the plunger 24 to a predetermined location, filling the chamber with medication and then applying force against the flange so as to move the plunger 24 forward within the chamber. It will be appreciated that while a syringe is one type of device that can be used with the transfer device of the present invention for containing a dose of medication, there are a number of other types of devices that can equally be used. Therefore, the discussion of syringe 10 is meant to be only illustrative and not limiting in any manner.
Typically, a drug is provided of the shelf in solid form within an injectable drug vial that is initially stored in a drug cabinet or the like. To prepare an injectable unit dose of medication, a prescribed amount of diluent (water or some other liquid) is added to the vial to cause the solid drug to liquefy. Mixing and agitation of the vial contents is usually required. This can be a time consuming and labor intensive operation since first it must be determined how much diluent to add to achieve the desired concentration of medication and then this precise amount needs to be added and then the vial contents need to be mixed for a predetermined time period to ensure that all of the solid goes into solution. Thus, there is room for human error in that the incorrect amount of diluent may be added, thereby producing medication that has a concentration that is higher or lower than it should be. This can potentially place the patient at risk and furthermore, the reconstitution process can be very labor intensive since it can entail preparing a considerable number of medication syringes that all can have different medication formulations. This also can lead to confusion and possibly human error and also is an opportunity for microbial contamination when performed by hand.
If the medication needs to be reconstituted, the medication initially comes in a solid form and is contained in an injectable drug vial and then the proper amount of diluent is added and the vial is agitated to ensure that all of the solid goes into solution, thereby providing a medication having the desired concentration. The drug vial is typically stored in a drug cabinet or the like and is then delivered to other stations where it is processed to receive the diluent. As is known, the drug vial typically includes a pierceable septum that acts as a seal and prevents unwanted foreign matter from entering into the drug vial so as to contaminate the contents thereof as well as keeping the contents safely within the interior of the drug vial when the drug is stored or even during an application. The septum is typically formed of a rubber material that can be pierced by a sharp transfer device to permit communication with the interior of the drug vial and then when the transfer device is removed the small piercing hole seals itself due to the material properties of the septum. The sharp transfer device is typically a sharp tip of a cannula and over time, repeated piercing of the septum by the sharp cannula point can result in a breakdown of the integrity of the septum. In other words, repeated piercing of the septum can result in the septum losing some of its sealing properties and thus, leakage, etc. becomes possible when the drug vial is mishandled or inverted, as it can be during drug preparation and agitation operations.
What is needed in the art and has heretofore not been available is a system and method for automating the medication preparation process and more specifically, an automated apparatus for reconstituting and then delivering a prescribed amount of medication to a syringe or the like and one which overcomes the foregoing problems and which ensures that the connection between the cannula or the like and the drug vial remains robust over time.